Food Raw Materials: Cereals, Pulses, Fruits and Vegetables
What the exam tests
Questions here target raw-material selection, structure and composition, maturity indices, and the link between raw material quality and processing yield. You should know the parts of a cereal grain, why wheat gluten and rice amylose matter, how pulses carry antinutritional factors, and how climacteric fruit ripening changes handling.
Core rules and concepts
- A cereal kernel has bran (pericarp and aleurone), endosperm and germ; wheat endosperm proteins form gluten, while rice quality is often linked to amylose content.
- Pulse milling removes husk and splits the cotyledon into dhal; trypsin inhibitor in soybean and phytate in pulses are reduced by soaking, germination, cooking or fermentation.
- Fruits are climacteric (banana, mango, tomato) or non-climacteric (citrus, grapes); climacteric fruit ripens after harvest with an ethylene peak, so storage temperature and ethylene control matter.
- Maturity indices include days after planting, firmness, starch-iodine test, total soluble solids and acidity; over-mature produce bruises and loses yield.
Worked example
100 kg paddy contains 20 kg husk, 8 kg bran, 2 kg germ and 1 kg handling loss. Milled rice = 100 minus (20 + 8 + 2 + 1) = 69 kg, a 69% milling yield. If the miller sells husk at Rs 2/kg, bran at Rs 15/kg and germ at Rs 10/kg, by-product value = (20 x 2) + (8 x 15) + (2 x 10) = Rs 180. The rice itself is 69 kg; the economics must include both rice and by-products, not rice alone.
Traps
Calling husk bran; using moisture content and dry matter interchangeably; treating all fruits as climacteric; selecting pulses only by colour and ignoring insect damage or hard seeds.